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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.print.attribute;

import java.io.Serializable;

import java.util.Date;

/**
 * Class DateTimeSyntax is an abstract base class providing the common
 * implementation of all attributes whose value is a date and time.
 * <P>
 * Under the hood, a date-time attribute is stored as a value of class <code>
 * java.util.Date</code>. You can get a date-time attribute's Date value by
 * calling {@link #getValue() getValue()}. A date-time attribute's
 * Date value is established when it is constructed (see {@link
 * #DateTimeSyntax(Date) DateTimeSyntax(Date)}). Once
 * constructed, a date-time attribute's value is immutable.
 * <P>
 * To construct a date-time attribute from separate values of the year, month,
 * day, hour, minute, and so on, use a <code>java.util.Calendar</code>
 * object to construct a <code>java.util.Date</code> object, then use the
 * <code>java.util.Date</code> object to construct the date-time attribute.
 * To convert
 * a date-time attribute to separate values of the year, month, day, hour,
 * minute, and so on, create a <code>java.util.Calendar</code> object and
 * set it to the <code>java.util.Date</code> from the date-time attribute. Class
 * DateTimeSyntax stores its value in the form of a <code>java.util.Date
 * </code>
 * rather than a <code>java.util.Calendar</code> because it typically takes
 * less memory to store and less time to compare a <code>java.util.Date</code>
 * than a <code>java.util.Calendar</code>.
 * <P>
 *
 * @author Alan Kaminsky
 */
public abstract class DateTimeSyntax implements Serializable, Cloneable {

  private static final long serialVersionUID = -1400819079791208582L;

  // Hidden data members.

  /**
   * This date-time attribute's<code>java.util.Date</code> value.
   *
   * @serial
   */
  private Date value;

  // Hidden constructors.

  /**
   * Construct a new date-time attribute with the given
   * <code>java.util.Date </code> value.
   *
   * @param value <code>java.util.Date</code> value.
   * @throws NullPointerException (unchecked exception) Thrown if <CODE>theValue</CODE> is null.
   */
  protected DateTimeSyntax(Date value) {
    if (value == null) {
      throw new NullPointerException("value is null");
    }
    this.value = value;
  }

  // Exported operations.

  /**
   * Returns this date-time attribute's <code>java.util.Date</code>
   * value.
   *
   * @return the Date.
   */
  public Date getValue() {
    return new Date(value.getTime());
  }

  // Exported operations inherited and overridden from class Object.

  /**
   * Returns whether this date-time attribute is equivalent to the passed in
   * object. To be equivalent, all of the following conditions must be true:
   * <OL TYPE=1>
   * <LI>
   * <CODE>object</CODE> is not null.
   * <LI>
   * <CODE>object</CODE> is an instance of class DateTimeSyntax.
   * <LI>
   * This date-time attribute's <code>java.util.Date</code> value and
   * <CODE>object</CODE>'s <code>java.util.Date</code> value are
   * equal. </OL>
   *
   * @param object Object to compare to.
   * @return True if <CODE>object</CODE> is equivalent to this date-time attribute, false otherwise.
   */
  public boolean equals(Object object) {
    return (object != null &&
        object instanceof DateTimeSyntax &&
        value.equals(((DateTimeSyntax) object).value));
  }

  /**
   * Returns a hash code value for this date-time attribute. The hashcode is
   * that of this attribute's <code>java.util.Date</code> value.
   */
  public int hashCode() {
    return value.hashCode();
  }

  /**
   * Returns a string value corresponding to this date-time attribute.
   * The string value is just this attribute's
   * <code>java.util.Date</code>  value
   * converted to a string.
   */
  public String toString() {
    return "" + value;
  }

}
